Vehicles, such as automobiles, light-duty trucks, and heavy-duty trucks, play an important role in the lives of many people. To keep vehicles operational, some of those people rely on vehicle technicians to diagnose and repair their vehicle.
Vehicle technicians use a variety of tools in order to diagnose and/or repair vehicles. Those tools may include common hand tools, such as wrenches, hammers, pliers, screwdrivers and socket sets, or more vehicle-specific tools, such as cylinder hones, piston ring compressors, and vehicle brake tools. The tools used by vehicle technicians may also include electronic tools such as a digital voltage-ohm meter (DVOM) or a vehicle scan tool that communicates with an electronic control unit (ECU) within a vehicle.
Modern vehicles have evolved into very complex machines with thousands of various parts that perform a vast array of operations that permit the vehicle to be operated by the user. Additionally, more and more vehicle operations that previously were controlled by mechanical interactions are instead being controlled by electronic control circuits and logic. As with any such complex machine, malfunctions may occur in one or more parts of the vehicle from time to time, including the electronic control circuits.
As a result, vehicle technicians must now rely on sophisticated electronic equipment to diagnose and repair vehicular malfunctions. In order to ease the mechanic's access to the electronic equipment within the vehicle, modern vehicles include an on-board diagnostic port (OBD port) or a diagnostic link connector (DLC). An OBD port or DLC generally comprises a plug-in type connector that is coupled to an on-board computer within the vehicle. The on-board computer is then coupled to various sensors at various places within the vehicle. The sensors can report present operating characteristics of vehicle elements and/or sense the existence of error conditions or malfunctions of the various vehicle elements. By plugging in an appropriate scanner device into the OBD or DLC, status or error codes can be retrieved from the OBD or DLC. These error codes may provide information as to the source of a malfunction in the electronic control circuits in the vehicle.
In addition to obtaining error codes and other diagnostic information from the OBD and/or DLC, portions of a scanner may interface with one or more of the vehicle's signal lines in order to provide instructions or communicate with a vehicle operator. For example, such signal lines may serve to drive incandescent light bulbs or light emitting diodes (LEDs) that may be visible to a vehicle operator. But like other vehicle elements, these signal lines may also be subject to error condition or malfunction (e.g., an electrical short) whereupon connecting the scanner device to the vehicle would result in irreversible damage to the scanner. Thus, methods and systems for preventing and/or eliminating such error conditions may be desired.